BALTIMORE (WJZ) — It could be a promising way to stop a deadly disease–swapping out defective genes with healthy ones.

Jessica Kartalija reports some are concerned it could be used to enhance genetics.

At Oregon Health Sciences University, scientists produced five monkeys using the experimental DNA replacement.

If approved, the technique would next be used to get rid of defective genes in a human egg, replacing them with good genes from another woman. That egg would be fertilized and placed back into the mother.

The baby would have genes from three different people.

“Instead of fixing, we could actually replace it with donor mitochondria genes,” said Dr. Shoukhrat Mitalipov.

The child would still inherit most of its parents’ traits, like eye color and height, but the donor’s DNA would replace some bad genes that cause some inherited diseases, like epilepsy.

“These eggs will have basically mostly the DNA–which is in the nucleus—will come from patients from family–more than 99 percent–but this one percent of genes will be donor-originated,” Mitalipov said.

Critics will urge the government not to improve this for moral and ethical reasons, fearing the next step will be designer babies, where parents choose eye color and sports ability.

Some are against it, though, for more fundamental reasons.

“We are opposed to anything that has to do with testing of the earliest stages of life. We believe that life begins at conception, and what’s when all the DNA is present and nothing more is added,” one woman said.

But scientists say the focus is on women who have already had a child with defective genes.

The FDA is holding a two-day meeting next week to discuss how to test three person embryo fertilization in humans.